Diversity of Chemical Structures and Biosynthesis of Polyphenols in Nut-Bearing Species.

Chaiwat Aneklaphakij,Veena Satitpatipan,Mutsumi Watanabe,Alisdair R Fernie,Somnuk Bunsupa,Takayuki Tohge,Thomas Naake,Tomoki Saigo

doi:10.3389/fpls.2021.642581

Abstract

Nuts, such as peanut, almond, and chestnut, are valuable food crops for humans being important sources of fatty acids, vitamins, minerals, and polyphenols. Polyphenols, such as flavonoids, stilbenoids, and hydroxycinnamates, represent a group of plant-specialized (secondary) metabolites which are characterized as health-beneficial antioxidants within the human diet as well as physiological stress protectants within the plant. In food chemistry research, a multitude of polyphenols contained in culinary nuts have been studied leading to the identification of their chemical properties and bioactivities. Although functional elucidation of the biosynthetic genes of polyphenols in nut species is crucially important for crop improvement in the creation of higher-quality nuts and stress-tolerant cultivars, the chemical diversity of nut polyphenols and the key biosynthetic genes responsible for their production are still largely uncharacterized. However, current technical advances in whole-genome sequencing have facilitated that nut plant species became model plants for omics-based approaches. Here, we review the chemical diversity of seed polyphenols in majorly consumed nut species coupled to insights into their biological activities. Furthermore, we present an example of the annotation of key genes involved in polyphenolic biosynthesis in peanut using comparative genomics as a case study outlining how we are approaching omics-based approaches of the nut plant species.

Highlights

Nuts, such as chestnut and hazelnut, are oil-rich seeds comprising of an edible fruit with a hard outer shell attached to a cupule
Nuts are regarded as treasured food crops due to their high contents of potential bioactive components which are able to promote human health benefit
In our summary of the chemical diversity of nut polyphenols, flavonoids are found as the major structurally diversified polyphenols in both aglycone and decorated forms among seeds of nut plant species. With regard to the latter, the glycoside is the main category of polyphenolic derivatives

Summary

Introduction

Nuts, such as chestnut and hazelnut, are oil-rich seeds comprising of an edible fruit with a hard outer shell attached to a cupule. Nuts are regarded as treasured food crops due to their high contents of potential bioactive components which are able to promote human health benefit.

Results

Conclusion